We propose to develop a large, comprehensive bank of placental and fetal specimens from spontaneous abortions and ectopic pregnancies, which includes detailed clinical data (and parental specimens whenever possible). Fetal and placental tissues (and RNA or DNA extracted from them) will be essential for our ongoing research into the causes of early pregnancy loss. Ultimately, the material collected may prove to be a valuable source of stem cells for fetal tissue transplantation (especially in Utah where relatively few pregnancies are terminated "electively"). Our multi-disciplinary team will exhaustively characterize specimens in the bank for the prevalence and significance of known and suspected etiologic factors. A drug recall history and a urine toxicology screen will be obtained from every consenting woman. Embryonic and fetal tissues will be analyzed for chromosomal abnormalities will undergo a detailed teratology/dysmorphology examination, and will be cultured for relevant bacteria and viruses. DNA amplification techniques will also be used as a complimentary approach to screen the tissues for microorganisms. Polymorphic DNA markers will be used to compare maternal, paternal, and fetal samples to screen for genetic events which are not normally apparent on routine cytogenetic examination (such as isodisomy, microdeletions, and single gene mutations) Finally, we will test the feasibility of obtaining and culturing fetal hematopoietic progenitors using fetal liver from spontaneous abortions and ectopic pregnancies. The success or failure of these cultures will be compared with our success in culturing neonatal hematopoietic progenitors and will be correlated with the clinical data and the laboratory investigations. To prolong their availability of stem cells for transplantation, we will attempt long-term culture and cryopreservation of the hematopoietic progenitors.